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Medical Definition of Oculocutaneous albinism
1. An autosomal recessive deficiency of pigment in skin, hair, and eyes; in the tyrosinase negative type, there is an absence of tyrosinase; in the tyrosinase positive type, there is normal tyrosinase which cannot enter pigment cells; it is transmitted by an autosomal recessive inheritance. The compound heterozygote is normal so the two forms are not allelic. There are several types: type IA is characterised by absence of tyrosinase with life-long complete absence of melanin, marked photophobia, and nystagmus. Type IB, yellow albinism with low or absent tyrosinase; improves with age. Type II, with normal tyrosinase activity is the most common; hair darkens and nevi and freckles develop. Type III is characterised by absent tyrosinase but pigmentation of the iris in the first decade. Type IV in Africans with normal tyrosinase. Type V with red hair. Type VI, Hermansky-Padlak syndrome, with haemorrhage due to platelet deficiency and low to absent tyrosinase. Synonym: Hermansky-Pudlak syndrome type VI. (05 Mar 2000)
Lexicographical Neighbors of Oculocutaneous Albinism
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